DE2538818B2 - Process for promoting condensation and / or equilibration reactions of organosilicon compounds - Google Patents

Description

The invention relates to an improvement in the process for promoting condensation and / or equilibration reactions of organosilicon compounds containing Si-bonded oxygen by means of phosphorus nitride chlorides. The improvement is that the organopolysiloxanes prepared according to the invention are particularly resistant to oxidation. The improvement is achieved through the use of at least one hydroxyaryl compound

For example from FR-PS 10 95 070 and US-PS 28 30 967 it is known condensation · and / or Promote equilibration reactions using phosphorus-nitrogen compounds as catalysts. Under the Phosphorus-nitrogen compounds are the phosphorus nitride chlorides, which are often referred to as "phosphorus nitrile chlorides", because of their relative proportions easy accessibility is particularly preferred infer that the organopolysiloxanes produced in this way are very heat-resistant because the phosphorus-nitrogen compounds also act as oxidation stabilizers. The organopolysiloxanes produced according to the invention using phosphorus-nitrogen compounds however, they are even more resistant to oxidation. Furthermore, from FR-PS 13 67 464 and the GB-PS 10 64 021 Organopolysiloxanes, which are resistant to oxidation and via oxygen to silicon have bound aryl groups, known. The organopolysiloxanes prepared according to the invention should also have aryl groups bonded to silicon via oxygen. The method according to the invention can, however, be carried out with more easily accessible starting products and / or with less effort.

The invention relates to a process for promoting condensation and / or equilibration reactions of organosilicon compounds containing Si-bonded oxygen by means of phosphorus nitride chlorides, characterized in that at least part of the condensation and / or equilibration reactions using at least one hydroxyaryl compound which contains one hydroxyl group or two hydroxyl groups bonded directly to an optionally substituted aryl radical, can be carried out.

The method according to the invention was not obvious. It was to be expected that the hydroxy aryl compound would react with the phosphorus nitride chlorides and thus eliminate the catalytic effectiveness of the phosphorus nitride chlorides.

Condensation reactions of organosilicon compounds containing Si-bonded oxygen are

iü the reaction of Si-bonded hydroxyl groups with one another with the escape of water, further z. B. the reaction of an Si-bonded hydroxyl group with an Si-bonded alkoxy group with the escape of alcohol or with Si-bonded halogen with the escape of hydrogen halide. Equilibration reactions are understood to mean the rearrangements of siloxane bonds up to the establishment of an equilibrium of the arrangement of siloxane units
Organosilicon compounds that contain Si-bonded oxygen can be used in the context of the invention whose condensation and / or equilibration reactions have already been promoted by means of phosphorus nitride chlorides or other phosphorus-nitrogen compounds.

At the moment, however, and thus also within the scope of the process according to the invention, condensation and / or equilibration reactions of such Si-bonded oxygen-containing organosilicon compounds which are carried out by

jo the formula

HO (SiR ₂ O) _1n H

can be reproduced, optionally in a mixture with also Si-bonded oxygen-containing organosilicon compounds, which by the formula

R ₃ Si (OSiR ₂ ) ,, R

can be reproduced.

In these formulas, R in each case denotes the same or

various, monovalent, optionally substituted

Hydrocarbon residues and m is an integer in value

from 1 to 1000.

Although by the above and otherwise frequently

The formulas used are not shown, up to 5 mol percent of the diorganosiloxane (SiR ₂ O or OSiR ₂ -) units can be caused by other siloxane units, which are usually only present as more or less difficult to avoid impurities, such as RSiOj / r units, where R has the meaning given above, and / or SR} * «units.

Examples of monovalent hydrocarbon radicals R are alkyl radicals, such as methyl, ethyl, n-propyl, Isopropyl, η-butyl and sec-butyl radical; Alkenyl residues, like the vinyl and allyl radicals; and aryl groups including alkaryl and aralkyl groups such as the phenyl and Benzyl radical and o-, p- and m-ToIylreste.

Examples of monovalent, substituted hydrocarbon radicals R are cyanoalkyl radicals, such as the beta-cyano ethyl residue; Haloalkyl radicals, such as the 3,33-trifluoropropyne radical; and haloaryl radicals, such as o-, m- iifld p-chlorophenyl radicals.

Because of the easy accessibility, at least 50% of the number of radicals R are preferably methyl radicals.

The remaining radicals R which may be present are preferably vinyl and / or phenyl radicals.

In the case of the phosphorus nitride chlorides used in the context of the process according to the invention, it can be

are those that have been prepared by reacting 400 parts by weight of phosphorus pentachloride with 130 parts by weight of ammonium chloride (see. "Reports of the German Chemical Society", 57th year, 1924, page 1345), and / or those that are produced by converting 2 moles of phosphorus pentachloride have been prepared with 1 mole of ammonium chloride (see US Pat. No. 3,839,388. Phosphorus nitride chlorides of the latter type are preferred

The phosphomitride chlorides are preferably used in amounts of 0.0001 to 0.1 percent by weight, in particular 0.003 to 0.5 percent by weight, each based on the total weight of the organosilicon compounds, their condensation and / or equilibration promoted should be used

For better distribution in the organosilicon compounds, their condensation and / or equilibration is to be promoted, and for easier dosing are those within the scope of the method according to the invention The phosphomitride chlorides used are expediently dissolved in a solvent which is inert towards the phosphorus nitride chlorides, the organosilicon compounds and the hydroxyaryl compounds used Such inert solvents are halogenated hydrocarbons or halogenated carbons that are liquid at room temperature and 760 mm Hg (absolute), such as tetrachloroethane, chloroform, methylene chloride or mixtures this solvent

Preferred examples of hydroxyaryl compounds, one or two hydroxyl groups bonded directly to a substituted aryl radical are included

(a) Phenols of the formula OH

(C) compounds of the formula OH

HO

where R 'has the formula given above and n "is 0 or an integer from 1 to 4, and (d) compounds of the formula

wherein R 'the methyl, methoxy, tert-butyl or tert-butoxy radical or a radical of the formula

-C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₃

-OC (CHj) ₂ CH ₂ C (CHj) ₃ or

R "'

where R "is oxygen, the methylene, isopropylene or sulfonyHOiS ^ radical, R '" the methyl, methoxy, tert-butyl or tert-butoxy radical or a radical the formula

-C (CHj) ₂ CH ₂ C (CH ₃₎ J -OC (CHj) ₂ CH ₂ C (CHj) J

K ..

πΌ or an integer from 1 to a maximum of 5 and p is O or 1, and π is an integer from 0 to 5,

(b) by 0 to 7 groups R ', where R' has the meaning given above, and 1 or 2 hydroxyl group ^) substituted naphthalenes,

LI (~ * \ Il

where R ', R "and η" each have the meaning given above.

In all of the formulas given above, the radicals R 'can be identical or different. Not through Residues of R 'of saturated carbon valences in the benzene nuclei are saturated by hydrogen

Specific examples of hydroxyaryl compounds (a) are

Phenol,

4-tert-butylphenol, 4-phenylphenol,

3-tert-butyl-4-hydroxyanisoI, 4- hydroxyanisole, 2-tert-butylphenol, 2,4-Di-tert-Butylphenol, 2,4-dimethyl-6-tert-butylphenol and

2,6-di-tert-butyl-4-diethylphenol. Specific examples of hydroxyaryl compounds (b) are

Alpha-Naphthol, beta-naphtol and

1,4-naphthol hydroquinone.

Specific examples of hydroxyaryl compounds (c) are $

Catechol (= chatechol), to hydroquinone, Resorcinol, Toluohydroquinone, Trimethylhydroquinone and 2,6-di-tert-butyl hydroquinone.

«5 Individual Examples of Hydroxyaryl Compounds (d) are

2 ^ -Bis- (4-hydroxyphenyl) -propane, Bis (4-hydroxyphenyl) sulfone, 2 ^ '- methylenebis (4-'nethyl-6-tert' butylphenol) and

4,4'-methylenebis (2,6-di-tert-

butylphenol).

Mixtures of different hydroxyaryl compounds, e.g. B. from 7 parts by weight of 4-phenylphenol and 13 parts by weight of 2,2-bis (4-hydroxyphe- nyl) propane can be used.

The hydroxyaryl compounds are preferably used in amounts of 0.001 to 10 mole percent, in particular 0.005 to 5 mol percent, based in each case on the total molar amount of the organosilicon compounds or, siloxane units whose condensation and / or equilibration is to be promoted, used for better distribution in the organosilicon compounds, their condensation and / or equilibration to be promoted, and for easier dosing, within the scope of the invention Process used hydroxyaryl compounds be dissolved in a polar, inert solvent. the

However, it is by no means absolutely necessary to use the hydroxyaryl compounds in the form of their solutions. Examples of polar, inert solvents are ketones that are liquid at room temperature and 760 mm Hg (absolute) and ^{boiling at at most 200 °} C. and 760 mm Hg (absolute), such as di-tert-butyl ketone; Ethers with the physical properties given above, such as di-tert-butyl ether and diethylene glycol dimethyl ether; and esters having the above physical properties such as ethyl acetate

It is not necessary that the hydroxyaryl compounds used according to the invention are already too Beginning of the conditioning reactions and / or equilibration reactions of organosilicon compounds, which contain Si-bonded oxygen, are present by means of phosphorus nitride chlorides in a mixture with organosilicon compounds and phosphorus nitride chlorides. the Hydroxyaryl compounds can, if appropriate, in the further course of the abovementioned reactions with the simultaneous addition of further phosphorus nitride chloride, added to the reaction mixture.

The [Condensations- and / or equilibration reactions are preferably up to 18O ⁰ C carried out at 0 to 2Cs) ⁰ C, especially at 80 ° C. The process of the invention can batchwise or continuously be carried out at atmospheric pressure or at higher or lower pressures.

In order to ensure a good distribution of the substances used in the process according to the invention in one another ensure, the mixture of these substances is expediently moved during the process according to the invention.

After carrying out the process according to the invention, that is to say after the reaction mixture has reached a viscosity of mostly 10 ³ to 5 χ 10 ⁷ cP at 25 ° C., in a manner known for example from US Pat. No. 3,398,176 or in DE-PS 25 24 041 described way the phosphorus nitride chlorides in the product by reaction with 1 to 1.5 gram moles of tertiary amines, such as triLutylamine, per gram equivalent of the phosphorus nitride chlorides or amines of the general formula present in the product

YHNC (CH ₃ MCH ₂ X) _3. *

wherein X is hydrogen and / or radicals of the formula -OGi ₃ , -N (CHj) ₂ , -C (CHj) ₃ , -QCHj) ₂ NHY and / or -OC (CHj) j, Y is hydrogen or the radical of the formula - Si (CH ₃ ) _{3 and e 0, 1, 2} or 3, such as tert-octylamine, and / or ammonia in amounts of 1 to 5 gram moles per gram equivalent of PNCI 2 in the phosphorus nitride chlorides used for conveying and / or equilibration with regard to their catalytic activity is rendered ineffective and the organopolysiloxanes prepared according to the invention are stabilized against changes in viscosity.

According to the method of the invention, for. B. Organopolysiloxane oils, ie end-blocked by triorgansiloxy groups, liquid at room temperature Diorganopolysiloxanes such as those used as lubricants or hydraulic fluids, and diorganopolysiloxanes which can be hardened by free radicals or by the addition of Si-bonded hydrogen to aliphatic multiple bonds or by condensation of groups which are condensation-transferring in so-called "two-component systems" or so-called "one-component systems" were produced.

The organosilicon compounds prepared according to the invention can also be mixed with other organosilicon compounds in order to achieve them stabilize.

The phosphorus nitride chloride used in the following examples was prepared as follows:

A mixture of 417 g (2 moles) of phosphorus pentachloride and 53.5 g (1 mole) ammonium chloride in 1000 ml Tetrachloroethane is 12 hours with an oil bath

ίο 160 ⁰ C heated to boiling under reflux. The volatile components are removed from the pale yellow solution thus obtained at 160 ° C and lowering the pressure to about 1 mm Hg (abs.). Yellowish crystals remain as a residue, which essentially consist of the compound of the formula

exist.

Cl ₃ PNPCl ₂ NPCi ₃ · PCIe Example 1

A mixture of 392 g of an in each terminal unit and an Si-bonded hydroxyl group-containing dimethylpolysiloxane with a viscosity of 140 c St at 25 ⁰ C, 8 g of 2 £ bis- (4-hydroxyphenyl) propane and 0.1 ml of a 25 weight percent solution of the Phosphonitrile chloride in methylene chloride is kneaded for one hour at 100 ⁰ C and 10 mm Hg (abs.) In this case, bound Si-hydroxyl groups increases by condensing the viscosity to about 10 ⁶ cP at 25 ° C. Then, 12 hours at 160 ⁰ C and 10 mm Hg (abs.) kneaded The initially white mass becomes clear with the formation of aryl groups bonded to silicon via oxygen. Its viscosity falls in this further kneading initially to 1,000 cps at 25 ° C and finally rises to 5 x 10 "cP at 25 ⁰ C in the Sun

obtained, highly viscous diorganopolysiloxane

(n'S = 1.410) at 140 ⁰ C and about 760 mm Hg (abs.) 0.2 ml of tert-octylamine kneaded 1 g of the thus obtained high-viscosity diorganopolysiloxane in 100 g of a trimethylsiloxy endblok leated dimethylpolysiloxane with a viscosity that corresponds to a plasticity of 540 mkp, kneaded In contrast to the same trimethylsiloxy groups, the mixture thus obtained is end-blocked dimethylpolysiloxane without the addition of oxygen silicon-bonded aryl groups-containing diorganopolysiloxane not yet after 4 days at 200 ° C gelled

Example 2

a) In a twin-screw kneader with a length of 3.5 m operated at 150 ° C. and 3 mm Hg (abs.) In the reaction zone, 801 per hour of a dimethylpolysiloxane each having a Si-bonded hydroxyl group in the terminal units

j5 with a viscosity of 110 cSt at 25 ° C, 331 per hour of a trimethylsiloxy end-blocked dimethylpolysiloxane with a viscosity of 100 cSt at 25 ° C, 64 ml per hour of a 25 percent by weight Solution of 4-phenylphenol in diethylene glycol dimer ethyl ether and ' ^q 0 ml per hour of a 1 weight percent solution of phosphorus nitride chloride in methylene chloride fed via a discharge screw a dimethylpolysiloxane mainly unblocked by trimethylsiloxy groups into the discharge pipe a viscosity of 131 50OcP at 25 ° C. By means of a gear pump mounted on the Ausgangsrci'r is the viscous dimethylpolysiloxane, which still has a temperature of almost 150 ⁰ C, with each 8OmI

Mixed hour of a 4 weight percent solution of tert-octylamine. A sample of the thus obtained Dimethylpolysiloxane has not yet gelled after 108 days at 200 ° C.

b) The procedure described under a) is repeated, with the modification that instead of 64 ml per hour of a solution of 4-phenylphenol 64 ml per hour of a 25 weight percent solution of 2,4-di-tert-butylphenol in diethylene glycol dimethyl ether in the twin screw kneader are introduced . The dimethylpolysiloxane obtained in this way, predominantly end-blocked by trimethylsiloxy groups, has a viscosity of 139,750 cP at 25 ° C. A sample of the dimethylpolysiloxane obtained in this way gels only after 60 days of heating at 200 ° C. 1 ->

c) The procedure described under a) is repeated, with the modification that no hydroxyaryl compound is used. The thus obtained more or less completely by trimethylsiloxy end-blocked dimethylpolysiloxane having a 2 »viscosity of 166 00OcP at 25 ° C and gelled already after 16 days of heating at 200" C.

At game 3

A mixture of 400 g of an in each terminal unit and an Si-bonded hydroxyl group-containing dimethylpolysiloxane with a viscosity of 90 cSt at 25 ° C and 0.05 ml of 25gewichtsprozentigen solution of the phosphonitrilic chloride jn in methylene chloride for 30 minutes at 8O ⁰ C and 10 mm Hg (abs.) kneaded. The viscosity increases to over 10 * cP at 25 ° C. 7 g of 4-phenylphenol and 13 g of 2,2-bis- (4-hydroxyphenyl) -propane and a further 0.05 ml of the 25 weight percent solution of phosphorus nitride chloride in methylene chloride are added to the highly viscous dimethylpolysiloxane obtained in this way, and for one hour 180 ° C and 10 mm Hg (abs.) Kneaded. The viscosity falls to 47OcP at 25 ° C. 0.2 ml of tri-2-ethylhexylamine are mixed into the dimethylpolysiloxane thus obtained, w

Example 4

A mixture of 400 g of a dimethylpolysiloxane having a Si-bonded hydroxyl group in each of the terminal * => units with a viscosity of 90 cSt at 25 ° C, 7 g of a dimethylpolysiloxane end-blocked by trimethylsiloxy groups with a viscosity of 100 cSt at 25 ° C and 0.05 ml of the 25 percent strength by weight solution of phosphorus nitride chloride in methylene chloride is kneaded for 30 minutes at 80 ° C. and 10 mm Hg (absolute). The viscosity rises to about 10-10 ⁶ CP at 25 ° C. 20 g of 2,6-di-tert-butylphenol and 0.1 ml of the 25 percent strength by weight solution of phosphorus nitride chloride in methylene chloride are added to the highly viscous dimethyl pysiloxane obtained in this way. The mixture is then kneaded for 6 hours at 120 ° C. under the pressure of the surrounding atmosphere. The viscosity falls to 115,000 cP at 25 ° C. 0.7 ml of tert-octylamine are mixed into the dimethylpolysiloxane thus obtained

5 g of the dimethylpolysiloxane thus obtained and reacted with 2,6-di-tert-butylphenol are stirred into 100 g of a dimethylpolysiloxane end-blocked by trimethylsiloxy groups and having a viscosity of 100,000 cP at 25 ° C. The mixture obtained in this way is only at 220 after 20 days gelled ° C, while that by trimethylsiloxy endblok kierte dimethylpolysiloxane having a viscosity voi 100,000 cP at 25 ⁰ C without the above additive erwähntei already after 10 days at 220 ° C to gel.

Example 5

The procedure described in Example 4 would be repeated with the modifications that instead of the 201 use 2,6-di-tert-butylphenol 20 g 4-cumylphenol and after adding the amine in a short- path distillation unit at 200 ° C. and 10-> mmHg (abs.) unreacted phenol is distilled off. The mixture of: 5 g of the dimethylpolysiloxane thus obtained, reacted with 4-cumylphenol and having a viscosity of 480 cP at 25 ° C. and 100 g of the dimethylpolysiloxane end-blocked by trimethylsiloxy groups with a viscosity of 100,000 cP at 25 ° C. is even after 20 days not gelled at 22O ⁰ C.

Example 6

The procedure given in Example 5 is repeated with the modification that instead of 20 f 4-Ciimylphpnnl? 0 g HyHrnrhinnnmnnomprhylJithe! be used. The mixture of 5 g of the se obtained, vice versa with hydroquinone monomethyl ether set and a viscosity of 32OcP at 25 ° C having dimethylpolysiloxane and 100 g of the durcr Trimethylsiloxy end-blocked Dimethylpoly siioxans with a viscosity of 100,000 cP at 25 ° C is' not yet gelled even after 20 days at 220 ° C.

Example 7

The procedure given in Example 5 is repeated with the modification that instead of the 20 § 4-cumylphenol 20 g of hydroquinone monobenzyl ether can be used. The mixture of 5 g of the se obtained, reacted with hydroquinone monobenzyl ether and a viscosity of 104OcP at 25 ° C containing dimethylpolysiloxane and 100 g of the dimethylpolysiloxane endlocked by trimethylsiloxy groups with a viscosity of 100,000 cP at 25 ° C is not yet gelled even after 20 days at 220 ° C.

Examples

The procedure given in Example 5 is repeated with the modification that 20 g of thymol are used instead of the 20 g of 4-cumylphenol. The mixture of 5 g of the dimethylpolysiloxane obtained in this way, reacted with thymol and having a viscosity of 35OcP at 25 ° C. and 100 g of the dimethylpolysiloxane end-blocked by trimethylsiloxy groups with a viscosity of 100,000 cP at 25 ° C. is even after 20 days at 220 ° C not yet gelled

Example 9

The procedure given in Example 5 is repeated with the modification that 20 g of phenol are used instead of the 20 g of 4-cumylphenol. The mixture of 5 g of the thus obtained unreacted phenol and a viscosity of 23OcP at 25 ° C comprising dimethylpolysiloxane and 100 g of trimethylsiloxy-terminated dimethylpolysiloxane having a viscosity of 10O ¹⁰⁰⁰ cP at 25 ° C isi even after 20 days at 220 ° C not yet gelled

Example 10

The procedure given in Example 5 is repeated with the modification that 20 g of alpha-naphthol are used instead of the 20 g of 4-cumylphenol. The mixture of 5 g of the obtained, reacted with alpha-naphthol and a viscosity of 38Or? having at 25 ° C and Dimethylpolysiioxans IUO g of trimethylsiloxy endblokkierten Dimethylpolysiioxans having a viscosity of 100,000 cP at 25 ° C even after 20 Ta _b 'it is not gelled at 220 ° C.

Example 11

The procedure given in Example 5 is repeated with the modification that instead of the 20 g 4-cumylphenol 20 g of 4-tert-octylphenol can be used. The mixture of 5 g of the thus obtained, with 4-tert-octylphenol reacted and a viscosity of 50OcP at 25 ° C having dimethylpolysiioxane and 100 g of the by trimethylsiloxy groups end-blocked dimethylpolysiloxane with a viscosity of 100,000 cP at 25 ° C is even after 40 Days not yet gelled.

Claims (2)

Patent claims: 1. Process for promoting condensation and / or equilibration reactions of organosilicon compounds, which contain Si-bonded oxygen, by means of phosphorus nitride chlorides, thereby characterized in that at least part of the condensation and / or equilibration reactions with the use of at least one hydroxyaryl compound which has a hydroxyl group or two hydroxyl groups bonded directly to an optionally substituted aryl radical contains, to be carried out. 2. The method according to claim 1, characterized in that the hydroxyaryl compounds are used in amounts of 0.001 to 10 mol percent, based on the total molar amount of the organosilicon compounds or siloxane units, the condensation and / or equilibration of which is to be promoted.